/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/

/*
 *  X.509 certificate writing
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */
/*
 * References:
 * - certificates: RFC 5280, updated by RFC 6818
 * - CSRs: PKCS#10 v1.7 aka RFC 2986
 * - attributes: PKCS#9 v2.0 aka RFC 2985
 */

#include "tls/config.h"

#if defined(MBEDTLS_X509_CRT_WRITE_C)

#include "tls/x509_crt.h"
#include "tls/oid.h"
#include "tls/asn1write.h"
#include "tls/sha1.h"

#include <string.h>

#if defined(MBEDTLS_PEM_WRITE_C)
#include "tls/pem.h"
#endif							/* MBEDTLS_PEM_WRITE_C */

/* Implementation that should never be optimized out by the compiler */
static void mbedtls_zeroize(void *v, size_t n)
{
	volatile unsigned char *p = v;
	while (n--) {
		*p++ = 0;
	}
}

void mbedtls_x509write_crt_init(mbedtls_x509write_cert *ctx)
{
	memset(ctx, 0, sizeof(mbedtls_x509write_cert));

	mbedtls_mpi_init(&ctx->serial);
	ctx->version = MBEDTLS_X509_CRT_VERSION_3;
}

void mbedtls_x509write_crt_free(mbedtls_x509write_cert *ctx)
{
	mbedtls_mpi_free(&ctx->serial);

	mbedtls_asn1_free_named_data_list(&ctx->subject);
	mbedtls_asn1_free_named_data_list(&ctx->issuer);
	mbedtls_asn1_free_named_data_list(&ctx->extensions);

	mbedtls_zeroize(ctx, sizeof(mbedtls_x509write_cert));
}

void mbedtls_x509write_crt_set_version(mbedtls_x509write_cert *ctx, int version)
{
	ctx->version = version;
}

void mbedtls_x509write_crt_set_md_alg(mbedtls_x509write_cert *ctx, mbedtls_md_type_t md_alg)
{
	ctx->md_alg = md_alg;
}

void mbedtls_x509write_crt_set_subject_key(mbedtls_x509write_cert *ctx, mbedtls_pk_context *key)
{
	ctx->subject_key = key;
}

void mbedtls_x509write_crt_set_issuer_key(mbedtls_x509write_cert *ctx, mbedtls_pk_context *key)
{
	ctx->issuer_key = key;
}

int mbedtls_x509write_crt_set_subject_name(mbedtls_x509write_cert *ctx, const char *subject_name)
{
	return mbedtls_x509_string_to_names(&ctx->subject, subject_name);
}

int mbedtls_x509write_crt_set_issuer_name(mbedtls_x509write_cert *ctx, const char *issuer_name)
{
	return mbedtls_x509_string_to_names(&ctx->issuer, issuer_name);
}

int mbedtls_x509write_crt_set_serial(mbedtls_x509write_cert *ctx, const mbedtls_mpi *serial)
{
	int ret;

	if ((ret = mbedtls_mpi_copy(&ctx->serial, serial)) != 0) {
		return (ret);
	}

	return (0);
}

int mbedtls_x509write_crt_set_validity(mbedtls_x509write_cert *ctx, const char *not_before, const char *not_after)
{
	if (strlen(not_before) != MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1 || strlen(not_after) != MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1) {
		return (MBEDTLS_ERR_X509_BAD_INPUT_DATA);
	}
	strncpy(ctx->not_before, not_before, MBEDTLS_X509_RFC5280_UTC_TIME_LEN);
	strncpy(ctx->not_after, not_after, MBEDTLS_X509_RFC5280_UTC_TIME_LEN);
	ctx->not_before[MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1] = 'Z';
	ctx->not_after[MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1] = 'Z';

	return (0);
}

int mbedtls_x509write_crt_set_extension(mbedtls_x509write_cert *ctx, const char *oid, size_t oid_len, int critical, const unsigned char *val, size_t val_len)
{
	return mbedtls_x509_set_extension(&ctx->extensions, oid, oid_len, critical, val, val_len);
}

int mbedtls_x509write_crt_set_basic_constraints(mbedtls_x509write_cert *ctx, int is_ca, int max_pathlen)
{
	int ret;
	unsigned char buf[9];
	unsigned char *c = buf + sizeof(buf);
	size_t len = 0;

	memset(buf, 0, sizeof(buf));

	if (is_ca && max_pathlen > 127) {
		return (MBEDTLS_ERR_X509_BAD_INPUT_DATA);
	}

	if (is_ca) {
		if (max_pathlen >= 0) {
			MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(&c, buf, max_pathlen));
		}
		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_bool(&c, buf, 1));
	}

	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));

	return mbedtls_x509write_crt_set_extension(ctx, MBEDTLS_OID_BASIC_CONSTRAINTS, MBEDTLS_OID_SIZE(MBEDTLS_OID_BASIC_CONSTRAINTS), 0, buf + sizeof(buf) - len, len);
}

#if defined(MBEDTLS_SHA1_C)
int mbedtls_x509write_crt_set_subject_key_identifier(mbedtls_x509write_cert *ctx)
{
	int ret;
	unsigned char buf[MBEDTLS_MPI_MAX_SIZE * 2 + 20];	/* tag, length + 2xMPI */
	unsigned char *c = buf + sizeof(buf);
	size_t len = 0;

	memset(buf, 0, sizeof(buf));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_pk_write_pubkey(&c, buf, ctx->subject_key));

	mbedtls_sha1(buf + sizeof(buf) - len, len, buf + sizeof(buf) - 20);
	c = buf + sizeof(buf) - 20;
	len = 20;

	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_OCTET_STRING));

	return mbedtls_x509write_crt_set_extension(ctx, MBEDTLS_OID_SUBJECT_KEY_IDENTIFIER, MBEDTLS_OID_SIZE(MBEDTLS_OID_SUBJECT_KEY_IDENTIFIER), 0, buf + sizeof(buf) - len, len);
}

int mbedtls_x509write_crt_set_authority_key_identifier(mbedtls_x509write_cert *ctx)
{
	int ret;
	unsigned char buf[MBEDTLS_MPI_MAX_SIZE * 2 + 20];	/* tag, length + 2xMPI */
	unsigned char *c = buf + sizeof(buf);
	size_t len = 0;

	memset(buf, 0, sizeof(buf));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_pk_write_pubkey(&c, buf, ctx->issuer_key));

	mbedtls_sha1(buf + sizeof(buf) - len, len, buf + sizeof(buf) - 20);
	c = buf + sizeof(buf) - 20;
	len = 20;

	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC | 0));

	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));

	return mbedtls_x509write_crt_set_extension(ctx, MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER, MBEDTLS_OID_SIZE(MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER), 0, buf + sizeof(buf) - len, len);
}
#endif							/* MBEDTLS_SHA1_C */

int mbedtls_x509write_crt_set_key_usage(mbedtls_x509write_cert *ctx, unsigned int key_usage)
{
	unsigned char buf[4], ku;
	unsigned char *c;
	int ret;

	/* We currently only support 7 bits, from 0x80 to 0x02 */
	if ((key_usage & ~0xfe) != 0) {
		return (MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE);
	}

	c = buf + 4;
	ku = (unsigned char)key_usage;

	if ((ret = mbedtls_asn1_write_bitstring(&c, buf, &ku, 7)) != 4) {
		return (ret);
	}

	ret = mbedtls_x509write_crt_set_extension(ctx, MBEDTLS_OID_KEY_USAGE, MBEDTLS_OID_SIZE(MBEDTLS_OID_KEY_USAGE), 1, buf, 4);
	if (ret != 0) {
		return (ret);
	}

	return (0);
}

int mbedtls_x509write_crt_set_ns_cert_type(mbedtls_x509write_cert *ctx, unsigned char ns_cert_type)
{
	unsigned char buf[4];
	unsigned char *c;
	int ret;

	c = buf + 4;

	if ((ret = mbedtls_asn1_write_bitstring(&c, buf, &ns_cert_type, 8)) != 4) {
		return (ret);
	}

	ret = mbedtls_x509write_crt_set_extension(ctx, MBEDTLS_OID_NS_CERT_TYPE, MBEDTLS_OID_SIZE(MBEDTLS_OID_NS_CERT_TYPE), 0, buf, 4);
	if (ret != 0) {
		return (ret);
	}

	return (0);
}

static int x509_write_time(unsigned char **p, unsigned char *start, const char *time, size_t size)
{
	int ret;
	size_t len = 0;

	/*
	 * write MBEDTLS_ASN1_UTC_TIME if year < 2050 (2 bytes shorter)
	 */
	if (time[0] == '2' && time[1] == '0' && time[2] < '5') {
		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start, (const unsigned char *)time + 2, size - 2));
		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_UTC_TIME));
	} else {
		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start, (const unsigned char *)time, size));
		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_GENERALIZED_TIME));
	}

	return ((int)len);
}

int mbedtls_x509write_crt_der(mbedtls_x509write_cert *ctx, unsigned char *buf, size_t size, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
	int ret;
	const char *sig_oid;
	size_t sig_oid_len = 0;
	unsigned char *c, *c2;
	unsigned char hash[64];
	unsigned char sig[MBEDTLS_MPI_MAX_SIZE];
	unsigned char tmp_buf[2048];
	size_t sub_len = 0, pub_len = 0, sig_and_oid_len = 0, sig_len;
	size_t len = 0;
	mbedtls_pk_type_t pk_alg;

	/*
	 * Prepare data to be signed in tmp_buf
	 */
	c = tmp_buf + sizeof(tmp_buf);

	/* Signature algorithm needed in TBS, and later for actual signature */
	pk_alg = mbedtls_pk_get_type(ctx->issuer_key);
	if (pk_alg == MBEDTLS_PK_ECKEY) {
		pk_alg = MBEDTLS_PK_ECDSA;
	}

	if ((ret = mbedtls_oid_get_oid_by_sig_alg(pk_alg, ctx->md_alg, &sig_oid, &sig_oid_len)) != 0) {
		return (ret);
	}

	/*
	 *  Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension
	 */
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_x509_write_extensions(&c, tmp_buf, ctx->extensions));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, tmp_buf, len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, tmp_buf, len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, tmp_buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 3));

	/*
	 *  SubjectPublicKeyInfo
	 */
	MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_pk_write_pubkey_der(ctx->subject_key, tmp_buf, c - tmp_buf));
	c -= pub_len;
	len += pub_len;

	/*
	 *  Subject  ::=  Name
	 */
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_x509_write_names(&c, tmp_buf, ctx->subject));

	/*
	 *  Validity ::= SEQUENCE {
	 *       notBefore      Time,
	 *       notAfter       Time }
	 */
	sub_len = 0;

	MBEDTLS_ASN1_CHK_ADD(sub_len, x509_write_time(&c, tmp_buf, ctx->not_after, MBEDTLS_X509_RFC5280_UTC_TIME_LEN));

	MBEDTLS_ASN1_CHK_ADD(sub_len, x509_write_time(&c, tmp_buf, ctx->not_before, MBEDTLS_X509_RFC5280_UTC_TIME_LEN));

	len += sub_len;
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, tmp_buf, sub_len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));

	/*
	 *  Issuer  ::=  Name
	 */
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_x509_write_names(&c, tmp_buf, ctx->issuer));

	/*
	 *  Signature   ::=  AlgorithmIdentifier
	 */
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_algorithm_identifier(&c, tmp_buf, sig_oid, strlen(sig_oid), 0));

	/*
	 *  Serial   ::=  INTEGER
	 */
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_mpi(&c, tmp_buf, &ctx->serial));

	/*
	 *  Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
	 */
	sub_len = 0;
	MBEDTLS_ASN1_CHK_ADD(sub_len, mbedtls_asn1_write_int(&c, tmp_buf, ctx->version));
	len += sub_len;
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, tmp_buf, sub_len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, tmp_buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 0));

	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, tmp_buf, len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));

	/*
	 * Make signature
	 */
	mbedtls_md(mbedtls_md_info_from_type(ctx->md_alg), c, len, hash);

	if ((ret = mbedtls_pk_sign(ctx->issuer_key, ctx->md_alg, hash, 0, sig, &sig_len, f_rng, p_rng)) != 0) {
		return (ret);
	}

	/*
	 * Write data to output buffer
	 */
	c2 = buf + size;
	MBEDTLS_ASN1_CHK_ADD(sig_and_oid_len, mbedtls_x509_write_sig(&c2, buf, sig_oid, sig_oid_len, sig, sig_len));

	if (len > (size_t)(c2 - buf)) {
		return (MBEDTLS_ERR_ASN1_BUF_TOO_SMALL);
	}

	c2 -= len;
	memcpy(c2, c, len);

	len += sig_and_oid_len;
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c2, buf, len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c2, buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));

	return ((int)len);
}

#define PEM_BEGIN_CRT           "-----BEGIN CERTIFICATE-----\n"
#define PEM_END_CRT             "-----END CERTIFICATE-----\n"

#if defined(MBEDTLS_PEM_WRITE_C)
int mbedtls_x509write_crt_pem(mbedtls_x509write_cert *crt, unsigned char *buf, size_t size, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
	int ret;
	unsigned char output_buf[4096];
	size_t olen = 0;

	if ((ret = mbedtls_x509write_crt_der(crt, output_buf, sizeof(output_buf), f_rng, p_rng)) < 0) {
		return (ret);
	}

	if ((ret = mbedtls_pem_write_buffer(PEM_BEGIN_CRT, PEM_END_CRT, output_buf + sizeof(output_buf) - ret, ret, buf, size, &olen)) != 0) {
		return (ret);
	}

	return (0);
}
#endif							/* MBEDTLS_PEM_WRITE_C */

#endif							/* MBEDTLS_X509_CRT_WRITE_C */
